Research suggests that one in 20 people infected with mild Covid in the first wave of the pandemic were left with persistent symptoms up to three years later.
American scientists found that respiratory and neurological problems were the common problems still reported by people affected by the virus in 2020.
And the researchers, who tracked more than 135,000 Americans with Covid, also found a 34 percent higher risk of problems with all organs among people most affected by Covid and hospitalized.
Experts today called the findings an “important new lesson” and warned that the virus “should not be trivialized.”
It comes as separate research also suggested Covid booster shots are only 52 per cent effective in preventing infection after four weeks. After five months this figure rises to 20 percent.
Dr. Ziyad Al-Aly, a clinical epidemiologist at the University of Washington and lead author of the study, said, “We’re not sure why the effects of the virus persist for so long.”
The latest ONS data on Covid infections shows that more than 80 per cent of Britons suffer from a runny nose when infected. Loss of taste or smell, one of the original telltale signs of the virus, accounts for just under a fifth of all recorded symptoms.
It comes as Covid cases continue to slowly rise across the UK, after infection rates fell during the spring. Earlier this month, health chiefs issued an alert about a new variant, dubbed FLiRT, which they had begun monitoring. It currently accounts for around 30 per cent of new cases in the UK.
‘Possibly it has to do with viral persistence, chronic inflammation, immune dysfunction or all of the above.
‘We tend to think of infections as mainly short-term illnesses with health effects that manifest at the time of infection.
‘Our data challenges this notion. I feel like Covid continues to teach us, and this is an important new lesson, that a brief, seemingly innocuous or benign encounter with the virus can still lead to health problems years later.
He added: “Addressing this knowledge gap is critical to improving our understanding of long Covid and will help inform care for people living with long Covid.”
US government data suggests that up to 10 percent of people infected with the virus have experienced long Covid.
The term, often self-diagnosed, was coined to refer to a series of symptoms following Covid infection, which can persist for months or even years after the initial infection.
Around 1.9 million people in the UK are reported to suffer from it, and the term covers everything from fatigue and shortness of breath to muscle and joint pain.
The researchers analyzed data from 114,000 veterans with mild Covid who did not require hospitalization, more than 20,000 patients hospitalized with the virus and 5.2 million veterans who never received a Covid diagnosis.
All were enrolled in the study between March and December 2020.
During a three-year follow-up, they found that the risk of long Covid was 23 percent one year after infection.
This figure fell to 16 percent or about one in six after two years.
Worryingly, they also found that among those who were not hospitalized, Covid had contributed to the loss of 10 years of healthy life per 1,000 people, three years after infection.
By comparison, those who were hospitalized with Covid had lost 90 years of healthy life per 1,000 people.
In the United States, heart disease and cancer cause about 50 years of loss of healthy life, while stroke contributes about 10 years per 1,000 people.
Writing in the diary, Nature medicineThe researchers said: “Although preventing severe disease is important, strategies are also needed to reduce the risk of post-acute and long-term health loss in people with mild Covid.”
However, they also acknowledged that the study primarily involved veterans who were “mostly older,” white and male and may not reflect other populations.
The participants also contracted the virus in 2020, an era before Covid vaccines, suggesting their infection may have been more severe.
Dr Al-Aly added: ‘Covid is a serious threat to people’s long-term health and well-being and should not be trivialised.
‘Even three years from now, you may have forgotten about Covid, but he hasn’t forgotten about you.
The term “Long Covid”, often self-diagnosed, was coined to refer to a series of symptoms following Covid infection, which can persist for months or even years after the initial infection. Around 1.9 million people in the UK are reported to suffer from it, and the term covers everything from fatigue and shortness of breath to muscle and joint pain.
‘People might think they are out of the woods, because they had the virus and experienced no health problems.
“But three years after infection, the virus could still wreak havoc and cause disease in the intestine, lungs or brain.”
It comes as separate research also suggested that Covid booster shots targeting the Omicron variants prevented infection in just over half of people.
Writing in the New England Journal of MedicineAmerican researchers found that the effectiveness was 52.2 percent after four weeks and prevented hospitalization in 66.8 percent of cases.
But infection prevention fell to 32.6 percent after 10 weeks and to just 20.4 percent after 20 weeks.
In comparison, effectiveness in preventing hospitalization decreased to 57.1 percent after 10 weeks.
It comes as Covid cases continue to slowly rise across the UK, after infection rates fell during the spring.
Earlier this month, health chiefs issued an alert about a new variant, dubbed FLiRT, which they had begun monitoring.
It currently accounts for around 30 per cent of new cases in the UK.
FLiRT also accounts for about a quarter of new cases in the US, surveillance data suggests.
Virologists use the term FLiRT to describe a family of different variants: KP.2, KP.3, JN.1.7, JN.1.1 and KP.1.1.
They are all descendants of the JN.1 variant that has dominated the UK in recent months. That same thing was nicknamed Juno.
Ministers have repeatedly said they will not resort to imposing lockdowns unless it is an apocalyptic variant.
A wall of immunity among the population, built by repeated waves of infection and vaccine rollouts, has given officials the confidence to consign pandemic-era measures to history.
Spikes in Covid cases can still cause mass illness across the country, causing chaos in schools, health services and public transport.
Officials are also not tracking the prevalence of the virus in the same way as before, as part of the Government’s initiation of pre-Covid normalities.